Impact of land-use practices on phytodiversity of mesic grasslands in a sub-mountainous region (Western Germany) [Elektronische Ressource] / vorgelegt von Camilla Wellstein

Informations

• Publié par: justus-liebig-universitat_giessen
• Publié le: 01 janvier 2007
• Nombre de lectures: 12
• Langue: English

Extrait

Impact of land-use practices on phytodiversity of mesic grasslands
in a sub-mountainous region (Western Germany)


Dissertation zur Erlangung des Doktorgrades
(Dr. rer. nat.)
der Naturwissenschaftlichen Fachbereiche
der Justus-Liebig Universität Gießen

durchgeführt am
Institut für Landschaftsökologie und Ressourcenmanagement
Professur für Landschaftsökologie und Landschaftsplanung

vorgelegt von
Dipl. Biol. Camilla Wellstein



Gießen 2006




Dekan: Prof. Dr. Peter R. Schreiner
1. Gutachter: PD Dr. Rainer Waldhardt
2. Gutachter: Prof. Dr. Gerd Esser


The doctoral thesis „Impact of land-use practices on phytodiversity of mesic grasslands in
a sub-mountainous region (Western Germany)” is based on the following three papers:


I. Wellstein, C., Otte, A. & Waldhardt, R.: Impact of site and management on the diversity of
Central European mesic grassland. Agriculture, Ecosystems & Environment – accepted.


II. Wellstein, C., Otte, A. & Waldhardt, R.: Seed bank diversity in mesic grasslands and their
relation to vegetation, management and site conditions. Journal of Vegetation Science –
accepted.


III. Wellstein, C., Otte, A. & Waldhardt, R.: The population structure of three perennial
grassland species (Pimpinella saxifraga L., Leontodon autumnalis L., Sanguisorba officinalis
L.) in relation to management and habitat conditions. Applied Vegetation Science – submitted.




In paper I, I had the main responsibility for design, field work, data analysis and writing. The
co-authors contributed valuable ideas and suggestions for this study.
In paper II and III, I had the main responsibility for design, field work, data analysis and
performed the writing, while the co-authors contributed valuable comments.

TABLE OF CONTENTS
Table of contents
1 General Introduction ....................................................................................................................... 1
1.1 Background ............................................................................................................................... 1
1.2 Objectives ... 5
2 Study area .............. 8
3 Methods ................ 12
3.1 Sampling of aboveground vegetation and other habitat variables .......................... 12
3.2 Soil nutrient analyses and ascertaining of other environmental parameters ....... 12
3.3 Seed bank analyses .............................................................................................................. 13
3.4 Assessment of population biological parameters ........................................................ 13
3.5 Data analysis .......................................................................................................................... 13
4 Impact of site and management on the diversity of Central
European mesic grassland .......................................................................................................... 15
4.1. Abstract .................................................................................................................................. 15
4.2. Introduction 16
4.3. Material and Methods ........................................................................................................ 17
4.4. Results ..... 21
4.5. Discussion ............................................................................................................................. 25
5 Seed bank diversity in mesic grasslands and their relation to vegetation,
management and site conditions ............................................................................................... 28
5.1 Abstract .... 28
5.2 Introduction ............................................................................................................................ 30
5.3 Material and Methods ......................................................................................................... 32
5.4 Results ..................................................................................................................................... 36
5.5 Discussion .............................................................................................................................. 42
6 The population structure of three perennial grassland species
(Pimpinella saxifraga L., Leontodon autumnalis L., Sanguisorba officinalis L.)
in relation to management and habitat conditions ............................................................ 50
6.1 Abstract .... 50
6.2 Introduction ............................................................................................................................ 52
6.3 Material and Methods 54
6.4 Results ...... 59
6.5 Discussion 64
7 General Discussion and Synthesis ............................................................................................ 69
8 Summary ............................................................................................................................................ 74
9 Zusammenfassung .......................................................................................................................... 75
10 References ........... 77

Acknowledgements ...... 87
GENERAL INTRODUCTION
1 General Introduction

1.1 Background

For centuries, semi-natural grasslands have been created and maintained by human land use in
Central Europe (Slicher van Bath, 1963). Due to their plant species richness they are highly
relevant for the maintenance of biodiversity at multiple spatial scales. Generally, low
productivity and recurrent disturbance by mowing or grazing are a prerequisite of high
species diversity, while simultaneously hampering competitive exclusion and allowing for
coexistence of many plant species (Huston 1994; Grime 2001). At the habitat scale, it has
been proved that increased productivity by fertiliser application as well as abandonment or
enhancement of disturbance frequency by mowing or grazing lead to changes in floristic
composition and finally to a loss in species-richness (e.g. Burel et al. 1998; Korneck et al.
1998; Mac Donald et al. 2000). In Central Europe grasslands declined strongly in number and
size over the five last decades due to abandonment of marginal agricultural areas, melioration
and subsequent arable use. The remaining grassland areas often underwent intensification of
land-use such as fertilisation by mineral fertiliser or manure, drainage or frequent mowing
(e.g. Burel et al. 1998; Korneck et al. 1998; Mac Donald et al. 2000). Consequently, many
types of unimproved semi-natural grasslands that were common several decades ago have
become extinct or fragmented. Besides the particularly endangered wet meadows and dry
calcareous grasslands, the formerly widespread mesic grasslands of the order
Arrhenatheretalia (Tüxen 1931) are also currently in decline (Burel et al. 1998; Poschlod &
Schumacher 1998; Mac Donald et al. 2000). This development has led to the inclusion of this
habitat type in the European Fauna-Flora-Habitat Directive of the European Union
(92/43/EEC, European Union 1992; Ssymank et al. 1998).
Particularly low-land grasslands were threatened by land use intensifications. In contrast,
marginal regions, mainly within mountainous areas, are less agriculturally favourable. Such
regions are traditionally associated with low-intensity management, and grassland habitats
still predominate the agricultural landscape (e.g. Cousins & Eriksson 2002; Vandvik & Birks
2002; SRU 2004). Furthermore, according to OECD (2004), the common agricultural policy
(CAP) reform is expected to ensure the maintenance of grassland areas. Due to these
preconditions, such regions offer unparalleled opportunities to study different management
regimes amongst other determinants influencing phytodiversity in mesic grasslands. The
Lahn-Dill Highlands of central Hesse, Germany, are a typical example of marginal rural
1GENERAL INTRODUCTION
landscapes: these are characterised by relatively unfavourable abiotic conditions for
cultivation, such as cool climate and shallow soils (Frede & Bach 1999). Furthermore,
unfavourable structural conditions for agriculture comprise small-scale part time farming
along with alternative incomes in the vicinity. Since the 1950s, the Lahn-Dill Highlands have
been subject to major agricultural land-cover changes, resulting in a decline in arable land and
an increase in grassland and fallow land (Waldhardt & Otte 2003; Hietel et al. 2005, in press;
Reger et al. accepted). In many places, non-intense grassland use has successively replaced
the traditional, extremely small-parcelled crop production and crop/grassland rotation. There
are different current grassland management regimes in the study area which provide strong
differences in disturbance impact. The management regimes range from hay meadows with
only one or two cuts per year to pastures grazed from May to September and silage meadows
mown three times a year.
Management has a considerable influence on almost all aspects of grassland dynamics
(Lennartson & Oostermeijer 2001). Hen